Definitive diagnosis for septic arthritis will be made following analysis of the joint fluid for a positive gram stain/culture and white blood cell (WBC) count consistent with infection (75,000-150,000 cells/mm3) as discussed above. Plain films of the involved joint will be acquired to evaluate for soft tissue edema, osteomyelitis, as well as to rule out other pathological involvement. Patients' blood sample will also be evaluated for central blood count (CBC), erythrocyte sedimentation rate (ESR), C- reactive protein (CRP), and cultures.